1. Field of the Invention
The invention relates to a liquid crystal display, and more particularly, to a positioning structure for positioning an optical film and a frame and related backlight module and LCD.
2. Description of the Prior Art
A liquid crystal display (LCD) has many advantages. It has been widely used in all kinds of electronic devices.
In an LCD having a LED backlight module and a narrow side frame, in order to solve a hotspot problem formed on the light guiding plate, the optical film is often placed on the frame. Please refer to FIG. 1, which is a diagram showing a backlight module according to the related art. The backlight module 100 comprises at least one optical film 10, a plastic frame 20, a back frame 30, a light guiding plate 40, and a Led light source 50. The light guiding plate 40 is placed inside the back frame 30. The Led light source 50 is placed on an inner wall 31 of the back frame 30 and near a light input surface of the light guiding plate 40. The lights generated from the LED light source are inputted into the light guiding plate 40 through the light input surface. A reflection plate 60 is installed between the light guiding plate 40 and the back frame 30, and is used to reflect the lights emitted from the light guiding plate 40 back to the light guiding plate 40. The plastic frame 20 and the back frame 30 are assembled to fix the light guiding plate 40, the LED light source 50, and the reflection plate 60 inside the back frame 30. A positioning pillar 26 is installed on the side frame 25 of the plastic frame 20, and is used to be placed through the positioning hole 12 of the optical film 10. In this way, the optical film 10 can be fixed in both X and Y directions.
It can be seen that the plastic frame 20 and the optical film 10 cannot be fixed in the Z direction (the direction of the thickness of the backlight module 100). This makes the optical film 10 unstable in the Z direction.